I'm a masters student currently deciding in which area should I focus on. So far my primary interest has been C* algebras and operator algebras (already have some knowledge on K-theory for C* algebras and Hilbert modules), but I always had some interest in geometry. When I learnt about the Gelfand representation theorem I thought there was a chance to mix both interests. I tried to read Alain Connes book I realized I was missing lots of prerequisites. I'd like to have at least a picture broad enough of this area to determine if I like it or not, what is the mininum I should know before I can do that?